Dual-polarized bidirectional rod antenna for diversity reception at street microcell base stations

Abstract

This paper proposes the DP-BIRA (dual-polarized bidirectional rod antenna) which has the optimum antenna beam shape for street microcells and minimizes degradation in the received signal power caused by the polarization mismatch at the street microcell base stations. The theoretical results given by the multi-ray model are verified; the optimum antenna configuration for the street microcell base station is a bidirectional rod antenna (BIRA) composed of radiating elements arrayed in the E-plane (vertical). When the inclination angle of the handy-phone antenna is 90 degrees, the signal power of the height diversity collinear antenna (HCA), which is commonly used for diversity reception at the PHS base stations, degrades up to about -15 dB, and the HCA cell length is reduced by almost half from that of the vertically-polarized incident wave. On the other hand, the DP-BIRA holds the received signal power almost constant against inclination, so almost the same cell length is realized regardless of the handy-phone inclination. A DP-BIRA is fabricated and tested in a street cell environment in an urban area to verify the validity of our design method and the usefulness of the DP-BIRA.